> Another difference is that most embedded modem products
> have an implied or contractual assurance that THE SAME PRODUCT will be
> available for a significant length of time. If you design a product to use
> a PCMCIA modem instead, you may get a significant cost savings, BUT you may
> end up pulling out your hair when your preferred modem is dropped and the
> new one you get isn't "quite" compatible.

John's really hit the nail on the head. Until last September I worked as a
software engineer for a manufacturer of dialup routers. They were building
most of their products using commodity PC hardware, hoping to take advantage
of the low costs.

There were several problems with that approach.

It would take months to qualify a particular motherboard or I/O board. By
the time it was in our production systems, the vendor had replaced their
product with a new, improved, and not fully compatible version, and we had
to go through qualification again. Or, in some cases we could convince the
vendor to continue selling us the old product if we were willing to pay a
premium price.

In some cases, we needed a customized version of a standard product, so we
paid premium prices for those as well as additional NRE charges.

And in one case, we designed our own board becasue we wanted a custom form
factor. But we were still using commodity "PC" chips, and they are
obsoleted almost as quickly as board level products.

The net result was that our materials costs were at least as high as they
would have been for custom non-PC hardware, but our labor and overhead costs
were much higher.